An act of retaliation/revenge by pissing on someone.
Most common occurences of peevenge happen in bars when drunken douchebags push a person into a urinal they're currently pissing in, splashing piss on them and having their dick touch the inside of the urinal wall, which prompts the person/pisser (in a fit of rage) to piss on the douchebag.
This technique is typically mastered by spinning a quick 360 in mid stream after the push has occured.
*Warning beware of Mock Pee post Peevenge
That drunken douche just pushed me into the urinal and my dick touched the inside of the urinal wall so I pissed on his leg!....Peevenge is a bitch!!!